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  1. (*steve*)

    PwM using microcontroller

    On all microcontrollers I'm aware of, an analog output is PWM. To make it an actul analog voltage you need to integrate the output over time (essentially employ an RC time constant much greater than the period of the PWM)
  2. (*steve*)

    This might be a fun disscussion :)

    I'd bet that impulse drive use PWM.
  3. (*steve*)

    This might be a fun disscussion :)

    On the basis that many civilizations have come up with their own version of warp drive, and that it allows one to travel the universe, I think it qualifies doubly as a universal motor. Therefore, if this is true, it may be AC/DC.
  4. (*steve*)

    I Want To Make A Device That Tells Me That Electricity Is Back

    One simple circuit would be to have a latching relay which removes power from a flashing light. So, when power is initially applied, the light starts flashing (powered via the n.c. contacts of a relay). Pressing a button pulls in a relay which uses the n.o. contacts to keep it powered. Once...
  5. (*steve*)

    What trends of Electrical Engineering Market that will make good money in 5 years.

    Lumping hydro with other renewables if not a distraction, it emphasises the issues with renewable power. Hydro can store energy in the form of potential energy. If hydro only worked while it was raining you wouldn't make the distinction. As I said, the problem is not that it's renewable, it's...
  6. (*steve*)

    What trends of Electrical Engineering Market that will make good money in 5 years.

    Renewables are not a crock of anything. The problem is intermittency. All electrical systems (at present) require a source of base load power. New Zealand provides much of their base load power from a renewable resource (hydro). In NZ's case they have increased the capacity to reduce the...
  7. (*steve*)

    Rechargeable Power Supply Question

    Read my reply to audio guru. Unfortunately his reply wasn't very helpful. You still need a dedicated charger. A "phone charger" is just a power supply, but one that is easily obtainable and suited to power many of these 1 cell lipo chargers.
  8. (*steve*)

    Aguadac voltage on filament pins

    Could there be some gas in the tube? edit: I'm not really sure if you're saying that there's a glow there when the socket is detached. There are several causes of blue, or violet glows, and most of them are not a problem. Gas in the tube generally is a problem, and this causes what is best...
  9. (*steve*)

    need basic schematic for a 12v gradual power up for small water pump

    Torque is proportional to current. A low value resistor in series with the motor (sufficient to drop maybe 1V under normal operating conditions) may be sufficient to reduce the starting torque. You need to be careful that it doesn't reduce it so much that the pump won't start. (actually I...
  10. (*steve*)

    Drop voltage on transistor base

    If you completely remove the connection to the base of the transistor, does the LED stay illuminated? If so, your first problem is one of: The transistor is connected incorrectly The transistor is PNP The transistor is damaged It is not a transistor Do you have a part number for Q1? Values...
  11. (*steve*)

    Drop voltage on transistor base

    Show us the circuit (the whole circuit)
  12. (*steve*)

    ETI magazine Feb 1979 - power supply (ETI-142)

    Don't do things from memory :-) It's an ETI-142 power supply. From Feb 1979 See here.
  13. (*steve*)

    Rechargeable Power Supply Question

    I thought someone might misread what I said. You still need the correct charging circuit as suggested by @kellys_eye but your power source can be a ubiquitous 5v phone charger (which is a power supply, not a charger). Perhaps @Audioguru you could try to be helpful and add clarification rather...
  14. (*steve*)

    Best place to buy parts and components?

    Digikey and mouser also offer free delivery on some orders to some places, so they can be worth looking at if you want parts that are hard to find elsewhere and/or have an order large enough to get free delivery. Yeah, they're in the US and you're not. But neither am I (you're closer)
  15. (*steve*)

    Calculating Resistance With Just Voltages? Basic DC Circuit Design

    The Arduino runs from 5V internally. Sure, it has a regulator which allows it to run from a higher voltage but there's no way that you can draw 1A from it without letting the smoke out. In fact, the maximum input voltage to an Arduino is generally limited by the power dissipation of the...
  16. (*steve*)

    Rechargeable Power Supply Question

    If going for a lithium battery, a single cell solution is great because it means there is no need to balance charge, and you can probably use a ubiquitous 5V phone charger.
  17. (*steve*)

    Conundrum using resistors? (Raw rookie)

    With this voltage, "a resistor and 4 LEDs" will not give you a robust solution. I would recommend 1 resistor per LED. If you look in our resource section you'll find one on LEDs that will tell you a lot about using LEDs and may be worth reading.
  18. (*steve*)

    ETI magazine Feb 1979 - power supply (ETI-142)

    Someone has dumped an ETI 712 power supply (I think) at my local hackerspace. Edit: it's an ETI-142 Does anyone have a copy of the magazine article(s) which describe it? Our state reference library may have it, but they note that this particular year is incomplete without giving details. The...
  19. (*steve*)

    Low-ESR 1uF electrolytic (hard to find)

    Mlcc is multi layer ceramic capacitor. When that project was designed ceramic capacitors with high capacitance would have been physically much larger. These days some very small and relatively high capacitance ceramic capacitors are available. Because their construction has many short layers...
  20. (*steve*)

    Low-ESR 1uF electrolytic (hard to find)

    1uF mlcc caps are easy to get these days. They have a very low ESR, but have capacitance that tends to vary with voltage, and can be microphonic. Their failure mode isn't so pyrotechnic :-). Surface mount mlcc's can fracture if mechanically stressed.
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